Image-guided therapy of a tissue

ABSTRACT

Image-guided therapy of a tissue can utilize magnetic resonance imaging (MRI) or another medical imaging device to guide an instrument within the tissue. A workstation can actuate movement of the instrument, and can actuate energy emission and/or cooling of the instrument to effect treatment to the tissue. The workstation and/or an operator of the workstation can be located outside a vicinity of an MRI device or other medical imaging device, and drive means for positioning the instrument can be located within the vicinity of the MRI device or the other medical imaging device. The instrument can be an MRI compatible laser or high-intensity focused ultrasound probe that provides thermal therapy to, e.g., a tissue in a brain of a patient.

RELATED APPLICATIONS

The present application is related to and claims the priority of U.S.Provisional Patent Application 61/955,121 entitled “Image-Guided Therapyof a Tissue” and filed Mar. 18, 2014. The present disclosure is alsorelated to U.S. Provisional Patent Application 61/955,124 entitled“Image-Guided Therapy of a Tissue” and filed Mar. 18, 2014. The contentsof each of the above listed applications are hereby incorporated byreference in their entireties.

BACKGROUND

Cancerous brain tumors can be “primary” tumors, meaning that the tumorsoriginate in the brain. Primary tumors include brain tissue with mutatedDNA that grows (sometimes aggressively) and displaces or replaceshealthy brain tissue. Gliomas are one type of primary tumor thatindicate cancer of the glial cells of the brain. While primary tumorscan appear as single masses, they can often be quite large,irregularly-shaped, multi-lobed and/or infiltrated into surroundingbrain tissue.

Primary tumors may not be diagnosed until the patient experiencessymptoms, including those such as headaches, altered behavior, andsensory impairment. However, by the time the symptoms develop, the tumormay already be large and aggressive.

One treatment for cancerous brain tumors is surgery. Surgery involves acraniotomy (i.e., removal of a portion of the skull), dissection, andtotal or partial tumor resection. The objectives of surgery may includeremoving or lessening of the number of active malignant cells within thebrain, or reducing a patient's pain or functional impairment due to theeffect of the tumor on adjacent brain structures. Not only can surgerybe invasive and accompanied by risks, for some tumors, surgery is oftenonly partially effective. In other tumors, surgery may not be feasible.Surgery may risk impairment to the patient, may not be well-tolerated bythe patient, and/or may involve significant costs, recovery time, andrecovery efforts.

Another treatment for cancerous brain tumors is stereotacticradiosurgery (SRS). SRS is a treatment method by which multipleintersecting beams of radiation are directed at the tumor such that, atthe point of intersection of the beams, a lethal dose of radiation isdelivered, while tissue in the path of any single beam remains unharmed.However, confirmation that the tumor has been killed is often notpossible for several months post-treatment. Furthermore, in situationswhere high doses of radiation may be required to kill a tumor, such asin the case of multiple or recurring tumors, it is common for thepatient to reach a toxic threshold for radiation dose, prior to killingall of the tumors. Reaching this toxic threshold renders furtherradiation is inadvisable.

SUMMARY

A system or method for effecting treatment to a tissue, in someimplementations, includes an automated drive mechanism with a holder tohold a treatment device (e.g., medical probe, ultrasonic applicator,laser fiber, etc.). In some implementations, the drive mechanism ismotorless and consists of thermal imaging compatible components. Thedrive mechanism, for example, can be configured without an electricmotor. The drive mechanism, in some examples, is included in an MRI orMRI head coil. The drive mechanism can be coupled to one or more wiresor umbilicals such that a translation of the one or more wires orumbilicals affects one or more of a longitudinal displacement of theholder and a rotation of the holder. A controller, in someimplementations, processes position control signals for setting and/ormonitoring a position of the holder (e.g., via an input interface to thewires or umbilicals), and issues subsequent position control signals tomanipulate positioning of the holder (e.g., via an output interface tothe wires or umbilicals).

The system or method, in some implementations, includes a guidemechanism that is attachable to a surface of a patient. The guidemechanism, for example, can include a base structure configured toremain stationary relative to the patient when the guide mechanism isattached to the surface of the patient in a locked state. The guidemechanism can further include a tilt portion that is coupled to the basestructure and provides an adjustable tilt between a trajectory of thedrive mechanism and the base structure. The guide mechanism can furtherinclude a rotation portion that provides an adjustable rotation of thetilt portion relative to the base structure.

The controller, in some implementations, is configured to process asequence of the position control signals to direct the guide mechanismto move the holder during treatment. For example, the controller can beprogrammed to move the holder to a first position for effecting thetreatment to the tissue at a first portion of the tissue that coincideswith the first position and then move the holder to a second positionfor effecting the treatment to the tissue at a second portion of thetissue that coincides with the second position.

During treatment, in some implementations, a workstation transmits theposition control signals to the controller and displays feedback images(e.g., MRI images and/or thermometry images) of the tissue to anoperator of the workstation. The workstation, for example, cancontinuously display the thermometry images of the tissue during thetreatment to the tissue at the first and second portions of the tissue,and while the holder moves between the first and second positions.

In some implementations, an imaging system receives images of the tissueand the treatment device and analyzes the images to monitor control ofpositioning and/or therapeutic energy delivery within the tissue. Forexample, the imaging system may process, in real time, the images of thetissue and the treatment device and the thermometry images of the tissueto forecast errors or interruptions in the treatment to the tissue.Responsive to the analysis, the imaging system may display, via theworkstation, a corresponding warning. Position control signals may beupdated and transmitted by the workstation to the controller based onone or more of the images, as the images are received by the workstationin real time.

In some implementations, treatment is delivered via an energy emissionprobe, such as an ultrasonic applicator or laser probe. The energyemission probe, in some examples, may include one or more emitters, suchas a radiofrequency emitter, a high-intensity focused ultrasoundemitter, a microwave emitter, a cryogenic cooling device, and aphotodynamic therapy light emitter. The energy emission probe mayinclude multiple emitters, where the emitters are longitudinally spacedwith respect to a longitudinal axis of the energy emission probe.

In some implementations, the energy emission of the probe can becontrolled to generate a number of different output patterns. Thedifferent patterns, for example, can include energy delivered via two ormore ultrasonic transducers and/or two or more laser fibers. Forexample, a laser probe may include a first laser fiber for outputting asymmetrical output pattern with respect to a longitudinal axis of thefirst laser fiber and a second laser fiber for outputting anasymmetrical output pattern with respect to a longitudinal axis of thesecond laser fiber. In another example, an ultrasonic applicator mayinclude a first ultrasonic transducer for outputting a first ultrasonicfrequency and a second ultrasonic transducer for outputting a secondultrasonic frequency.

The output pattern, in some implementations, includes a pulsed outputpattern. For example, a higher power density may be achieved withoutcausing tissue scorching by pulsing a high power laser treatment for xseconds with y seconds break between (e.g., for tissue in the immediatevicinity to cool down). In a particular example, the laser pattern maybe active for two seconds and inactive for one second.

In some implementations, the treatment pattern includes effectingtreatment while simultaneously moving the probe (e.g., linearly and/orrotationally). For example, an ultrasonic probe may be rotated while anemission pattern is simultaneously adjusted to effect treatment to adesired depth based upon a particular geometry of the region of interest(ROI). In this manner, for example, while the ultrasonic treatment beamis focused upon a radial portion of the tumor having a depth of 1.5centimeters, the power density of the HIFU probe may be tuned for thefirst treatment depth. Upon rotation, a second radial portion of thetumor may have a depth of 2 centimeters, and the power density of theHIFU probe may be increased accordingly to tune for the treatment depthof 2 centimeters.

An energy source may be included to generate energy for the probe. Insome implementations, the workstation transmits energy control signalsto the energy source. The workstation, for example, may be configured toprocess a sequence of the energy control signals to first effect asymmetrical treatment to the tissue with the probe and then effect anasymmetrical treatment to the tissue with the probe after thesymmetrical treatment. In a particular example, the workstation may beconfigured to process a sequence of position and laser control signalsto move the holder to a first position for effecting the treatment tothe tissue at a first portion of the tissue that coincides with thefirst position, effect a symmetrical treatment to the first portion ofthe tissue with the first laser fiber, move the holder to a secondposition for effecting the treatment to the tissue at a second portionof the tissue that coincides with the second position, and effect anasymmetrical treatment to the second portion of the tissue with thesecond laser fiber. During treatment, the workstation may be configuredto display thermometry images of the tissue continuously throughoutprocessing of the sequence of the position and energy control signalswhile effecting the symmetrical and asymmetrical treatments.

In some implementations, the system or method includes a guide sheathconfigured to accept two or more probes of different modalities as thetreatment device. The modalities may include, for example, laser,radiofrequency, high-intensity focused ultrasound, microwave, cryogenic,photodynamic therapy, chemical release and drug release. The guidesheath may include one or more off-axis lumens (holes) for positioningan emitting point of one or more of the number of probes at an off-axisangle.

The system or method may include one or more processors and circuitsthat embody aspects of various functions by executing correspondingcode, instructions and/or software stored on tangible memories or otherstorage products. A display may include various flat-panel displays,including liquid crystal displays.

In one aspect, the present disclosure relates to an apparatus includinga low profile skull anchor device configured to attach to an area of askull of a patient, the low profile skull anchor device including acentral opening for access to an entry formed in the skull of thepatient, where the low profile skull anchor device, upon attachment tothe area of the skull, protrudes from the area of the skull at a heightno greater than forty millimeters. The apparatus may further include aremovable guide stem configured to detachably connect to the low profileskull anchor device, the removable guide stem including a cylindricalopening, where upon connection of the removable guide stem to the lowprofile skull anchor device, the cylindrical opening is positionedsubstantially above the entry formed in the skull of the patient, andthe removable guide stem is configured to adjust a trajectory of thecylindrical opening in at least one of a tilt direction and a rotationdirection.

In some implementations, the low profile skull anchor device includes atleast three fastener positions for attaching the low profile skullanchor device to bone anchors set in the skull of the patient usingscrews. The low profile skull anchor device may include at least threeskull pins for maintaining a gap between the low profile skull anchordevice and a surface of the skull of the patient, thereby avoiding skincompression. The central opening of the low profile skull anchor devicemay be at least sixty millimeters in diameter.

In some implementations, the low profile skull anchor device includes atleast two fastener openings for connecting the removable guide stem tothe low profile skull anchor device. The removable guide stem mayinclude a ball joint for adjusting the trajectory of the cylindricalopening in both the tilt direction and the rotation direction. Theremovable guide stem may include a tilt adjustment mechanism foradjusting the trajectory of the cylindrical opening in a tilt directionand a separate rotation adjustment mechanism for adjusting thetrajectory of the cylindrical opening in a rotation direction. At leastone of the removable guide stem and the low profile skull anchor devicemay include a number of guide lines for aid in setting the trajectory ofthe cylindrical opening.

In some implementations, the apparatus includes a guide sheath, wherethe guide sheath is configured for insertion within the cylindricalopening of the removable guide stem, and the guide sheath includes atleast one hollow lumen extending between a proximal end of the guidesheath and a distal end of the guide sheath, where the at least onehollow lumen is configured for introduction of a neurosurgicalinstrument. The removable guide stem may include a lock mechanism forlocking the guide sheath to the removable guide stem at a selectedlinear depth of insertion within the cylindrical opening of a number oflinear depths of insertion available for selection. The distal end ofthe guide sheath may include two or more openings for deployment of theneurosurgical instrument.

In one aspect, the present disclosure relates to a head fixation systemincluding an upper ring portion including a nose indent for positioningthe nose of a patient when a head of the patient is encircled by thehead fixation system, and a lower ring portion including a number ofsupport posts, where the number of support posts are configured tosupport the head of the patient laid upon the lower ring portion, andthe lower ring portion is configured to lock to the upper ring portionafter positioning the head of the patient upon the number of supportposts.

In some implementations, the support posts are adjustably connected tothe lower ring portion via a number of slots, where the head fixationsystem includes more slots than support posts. Each support post of thenumber of support posts may include at least one connection point forconnecting a fastener. The at least one connection point may beconfigured for connection of a skull pin. Each support post of thenumber of support posts may include at least three connection points forconnecting a fastener, where a positioning of a fastener upon a firstsupport post of the number of support posts is user selectable. Uponpositioning the head of the patient between the lower ring portion andthe upper ring portion and locking the lower ring portion to the upperring portion, a user may tighten the fasteners to fix a position of thehead of the patient.

In some implementations, the head fixation system includes one or moreadditional upper ring portions, where the upper ring portion is selectedbased upon a size of the head of the patient. The lower ring portion maybe curved to provide at least forty degrees of angular head adjustmentupon placing the head fixation system within a fixation ring channel ofa patient table.

In one aspect, the present disclosure relates to a probe for use ineffecting intracranial high intensity focused ultrasound (HIFU)treatment, including at least one ultrasonic transducer, an acousticcoupling medium contacting the at least one ultrasonic transducer, and arigid external shaft for interstitial positioning of the at least oneultrasonic transducer, where the rigid shaft is up to 3.5 millimeters indiameter, and the at least one ultrasonic transducer is mounted withinthe rigid external shaft. The probe may be configured to driveultrasonic energy at least three centimeters into tissue for effectingthermal treatment of the tissue.

In some implementations, the at least one ultrasonic transducer ismounted in a side-firing position within the rigid external shaft. Theat least one ultrasonic transducer may include a linear array of threeor more ultrasonic transducers. The at least one ultrasonic transducermay be a planar transducer. The thermal treatment may include one ofcoagulation and cavitation.

The foregoing general description of the illustrative implementationsand the following detailed description thereof are merely exampleaspects of the teachings of this disclosure, and are not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of an exemplary layout of an MRI Control Room,an MRI Scan Room, and an MRI Equipment Room;

FIG. 2 is an illustration of a perspective view of a patient insertedinto an MRI, with a head fixation and stabilization system installed;

FIG. 3 illustrates a probe driver;

FIGS. 4A and 4B are flow charts illustrating an exemplary procedure fortreating a patient;

FIGS. 5A through 5E illustrate a low profile skull anchoring device andexemplary guide stems;

FIGS. 5F and 5G illustrate a guide stem and sheath configured tointerconnect with the low profile skull anchoring device;

FIGS. 5H and 5I illustrate example internal configurations of a guidesheath;

FIG. 6 is a flow chart illustrating an example method for determiningtrajectory adjustments based upon initial position and orientation ofprobe introduction equipment upon the skull of a patient;

FIGS. 7A through 7C illustrate a high intensity focused ultrasoundprobe;

FIGS. 8A and 8B illustrate a method for MR thermal monitoring usingoffset thermal imaging planes; and

FIG. 9 illustrates exemplary hardware of a workstation.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

In the drawings, like reference numerals designate identical orcorresponding parts throughout the several views.

As used herein, the words “a,” “an” and the like generally carry ameaning of “one or more,” unless stated otherwise. The term “plurality”,as used herein, is defined as two or more than two. The term “another”,as used herein, is defined as at least a second or more. The terms“including” and/or “having”, as used herein, are defined as comprising(i.e., open language). The term “program” or “computer program” orsimilar terms, as used herein, is defined as a sequence of instructionsdesigned for execution on a computer system. A “program”, or “computerprogram”, may include a subroutine, a program module, a script, afunction, a procedure, an object method, an object implementation, in anexecutable application, an applet, a servlet, a source code, an objectcode, a shared library/dynamic load library and/or other sequence ofinstructions designed for execution on a computer system.

Reference throughout this document to “one embodiment”, “certainembodiments”, “an embodiment”, “an implementation”, “an example” orsimilar terms means that a particular feature, structure, orcharacteristic described in connection with the example is included inat least one example of the present disclosure. Thus, the appearances ofsuch phrases or in various places throughout this specification are notnecessarily all referring to the same example. Furthermore, theparticular features, structures, or characteristics may be combined inany suitable manner in one or more examples without limitation.

The term “or” as used herein is to be interpreted as an inclusive ormeaning any one or any combination. Therefore, “A, B or C” means “any ofthe following: A; B; C; A and B; A and C; B and C; A, B and C”. Anexception to this definition will occur only when a combination ofelements, functions, steps or acts are in some way inherently mutuallyexclusive.

Further, in individual drawings figures, some components/features shownare drawn to scale to exemplify a particular implementation. For somedrawings, components/features are drawn to scale across separate drawingfigures. However, for other drawings, components/features are shownmagnified with respect to one or more other drawings. Measurements andranges described herein relate to example embodiments and identify avalue or values within a range of 1%, 2%, 3%, 4%, 5%, or, preferably,1.5% of the specified value(s) in various implementations.

The system or method may include one or more processors and circuitsthat embody aspects of various functions by executing correspondingcode, instructions and/or software stored on tangible memories or otherstorage products. A display may include various flat-panel displays,including liquid crystal displays.

The treatment of tumors by heat is referred to as hyperthermia orthermal therapy. Above approximately 57° C., heat energy needs only tobe applied for a short period of time since living tissue is almostimmediately and irreparably damaged and killed, for example through aprocess called coagulation, necrosis, or ablation. Malignant tumors,because of their high vascularization and altered DNA, are moresusceptible to heat-induced damage than healthy tissue. In otherprocedures, heat energy is applied to produce reversible cell damage.Temporary damage to cellular structures may cause the cells to be moreconducive to certain therapies including, in some examples, radiationtherapy and chemotherapy. Different types of energy sources, forexample, laser, microwave, radiofrequency, electric, and ultrasoundsources may be selected for heat treatment based on factors including:the type of tissue that is being treated, the region of the body inwhich the tissue to be treated is located, whether cellular death orreversible cellular damage is desired, the nature of energy applicationparameters for each source, and variability of the energy applicationparameters. Depending on these factors, the energy source may beextracorporeal (i.e., outside the body), extrastitial (i.e., outside thetumor), or interstitial (i.e., inside the tumor).

In interstitial thermal therapy (ITT), a tumor is heated and destroyedfrom within the tumor itself, energy may be applied directly to thetumor instead of requiring an indirect route through surrounding healthytissue. In ITT, energy deposition can be extended throughout the entiretumor. The energy can be applied to heat tissue in the treatment area toa temperature within a range of about 45° to 60° C.

An exemplary ITT process begins by inserting an ultrasound applicatorincluding one or more transducers into the tumor. The ultrasonic energyfrom the applicator may therefore extend into the tissue surrounding theend or tip including the one or more transducers to effect heatingwithin the tumor. In some implementations, the transducer(s) is/arealigned with an edge of the applicator and the applicator is rotatableso as to rotate the ultrasonic energy beam around the axis of theapplicator to effect heating of different parts of the tumor atpositions around the applicator. In other implementations or for otherapplications, the transducer(s) are presented on a tip of the applicatoror otherwise surrounding an inserted portion of the applicator.Depending upon the distribution of transducers, the applicator may bemoved longitudinally and/or rotated to effect heating of the tumor overa full volume of the targeted region.

In yet other implementations, the ultrasonic applicator is controlledand manipulated by a surgeon with little or no guidance apart from thesurgeon's memory of the anatomy of the patient and the location of thetumor. In still other implementations, images may be used during the ITTprocess to provide guidance for treatment. For example, locations oftumors and other lesions to be excised can be determined using amagnetic resonance imaging (MRI) system or computer tomography (CT)imaging system. During the ITT process, for example, MRI imaging can beused in real time to control or aid in guidance accuracy in an automatedor semi-automated fashion.

In some implementations, thermography (e.g., MR thermography, ultrasonicthermography, etc.) provides contemporaneous temperature feedbackregarding one or both of the targeted region and the surrounding tissueduring the ITT process. The temperature information, for example, can beused to monitor necrosis of tumor tissue while ensuring that surrounding(healthy) tissue suffers minimal to no damage. The temperature feedback,in some implementations, is used to perform either or both of:automating engagement of the ultrasonic energy and cooling functionalityof the ultrasonic applicator. In this manner, it is possible to controla temperature distribution or thermal dose in and around the tumor.

A system in accordance with this disclosure incorporates magneticresonance imaging (MRI) compatible energy emission probes and/or othertreatment devices and accessories for effective and controlled deliveryof thermal therapy to a wide range of locations and tumor sizes within abrain. The system, however, is not limited to MRI-guided thermaltherapy, as other therapies such as computer tomography (CT) can also beutilized. Further, this disclosure refers to an MRI scanner as anexample medical imaging machine, which may be referred to simply as anMRI.

I. Overview

The interface platform 102 is secured to a patient table 108 of an MRIsystem 110. The MRI system 110 may include a head coil and stabilizationsystem (herein stabilization system), an instrument adaptor, and an MRItrajectory wand. Exemplary MRI systems that can be utilized togetherwith the features discussed herein include those manufactured by SiemensAG, Munich, Germany (including the MAGNETOM AVANTO, TRIO, ESPREE, VERIOMRI Systems, which are trademarks and/or trade names of Siemens AG).Further, example MRI systems include those manufactured by GeneralElectric Company, Fairfield, Conn. (including the SIGNA, OPTIMA andDISCOVERY MRI systems, which are trademarks and/or trade names ofGeneral Electric Company).

In certain embodiments, all of the above components of the interfaceplatform 102 and the energy emission therapy equipment are MRIcompatible, which refers to a capability or limited capability of acomponent to be used in an MRI environment. For example, an MRIcompatible component operates and does not significantly interfere withthe accuracy of temperature feedback provided by the MRI systemoperating with exemplary flux densities including: magnetic fluxdensities of 1.5 T or 3.0 T, where no hazards are known for a specifiedenvironment (e.g., 1.5 T or 3.0 T). Compatibility can also be definedwith respect to one or more other magnetic flux densities, including atleast 0.5 T, 0.75 T, 1.0 T, 2 T, and 5 T.

In certain embodiments, the system electronics rack 104 includes cables,penetration panels and hardware that effectuates mechanical, electrical,and electronic operation of the energy emission therapy equipment andthe MRI system 110. The system electronics rack 104 may further be usedto power and route control signals and/or communications for the controlworkstation 106.

The workstation 106 includes a display that displays a user interface,e.g., a graphical user interface (GUI) and/or a command line interfacethat enables a user to plan a treatment procedure and interactivelymonitor the procedure, the interface platform 102, and the entire MRIsystem 110. In certain embodiments, the user interface also provides theuser, e.g., a medical professional, the ability to directly control theenergy emission therapy equipment including an energy source associatedtherewith, and therefore, enables directly control of the application ofthe therapy to the patient.

Turning to FIG. 2, an exemplary position of a patient on the patienttable 108 of the MRI system 110 is illustrated. The interface platform102 is secured to the patient table 108 together with a head coil 202and stabilization system, which is a head fixation device thatimmobilizes a patient's head. The stabilization system includes a headfixation ring 204. A probe 206 and probe driver 208 are coupled to probeintroduction equipment 210, and to the interface platform 102 viaumbilicals. A cable, for example, can be used to provide data, laser,fluid, etc. connections between the probe 206, probe driver 208, andinterface platform 102 and the electronics rack 104 in the MRI equipmentroom (as illustrated in FIG. 1).

The probe introduction equipment 210, in certain embodiments, includesat least a portion that is detectable by the MRI system (e.g., includedin temperature data that is displayed by an imaging portion of the MRIsystem) and is used for trajectory determination, alignment, andguidance of the probe 206. An MRI trajectory wand (e.g., an MRIdetectable, fluid-filled tube) may be placed into the probe introductionequipment 210, for example, to confirm a trajectory, associated with anintended alignment, to a targeted tissue region, via MRI. Afterconfirmation, the probe 206 may be introduced into the probeintroduction equipment 210 to effect surgery or therapy.

The probe 206 may be composed of MRI compatible materials that permitconcurrent energy emission and thermal imaging, and can be provided inmultiple lengths, cross-sectional areas, and dimensions. Types of probesthat can be utilized with the components and procedures discussed hereininclude RF, HIFU, microwave, cryogenic, and chemical release probes; thechemical release probes may include photodynamic therapy (PDT), and drugreleasing probes. Treatments in accordance with the descriptionsprovided in this disclosure include treatments that ablate (i.e.,“treat”) a tissue to destroy, inhibit, and/or stop one or more or allbiological functions of the tissue, or otherwise cause cell damage orcell death that is indicated by a structural change in cells of thetargeted tissue area. Ablation can be effected by laser, RF, HIFU,microwave, cryogenic, PDT and drug or chemical release. A correspondingprobe and/or other instrument, such as a needle, fiber or intravenousline can be utilized to deliver one or more of these ablation agentsintracorporeally or percutaneously and proximate to, in the vicinity of,abutting, or adjacent to a targeted tissue area so as to effecttreatment. The probe 206 can be a gas-cooled probe so as to controldelivery of the energy to the targeted tissue area. The length anddiameter of the probe 206 is preselectable based on the targeted tissuearea and/or the ROI. The probe 206, in some particular examples, can bea laser delivery probe that is used to deliver laser interstitialthermal therapy or a HIFU applicator that is used to deliver HIFUinterstitial thermal therapy.

The probe driver 208 controls positioning, stabilization andmanipulation of the probe 206 within a specified degree of precision orgranularity. Turning to FIG. 3, the components of the probe driver 208generally include a commander 302, umbilicals 304, a follower 306, and aposition feedback plug 308 that receives position feedback signals from,for example, potentiometers within the follower 306. The probe 206(illustrated in FIG. 2) can be inserted into the follower 306, and thefollower 306 can control a rotational and longitudinal alignment and/ormovement of the probe 206. The probe driver 208 can further include arotary test tool (not illustrated) that can be used during a self-testprocedure to simulate attaching a probe to the follower 306. Anexemplary probe driver that can be utilized in accordance with thevarious aspects presented in this disclosure is described in U.S. Pat.No. 8,728,092 to Qureshi, entitled “Stereotactic Drive System” and filedAug. 13, 2009, the entirety of which is incorporated herein byreference.

The probe driver 208 (illustrated in FIG. 2) is mounted to the interfaceplatform 102. The position feedback plug 308 (illustrated in FIG. 3)connects to the interface platform 102 in order to communicate theposition of the probe 206 to the user and/or the workstation 106(illustrated in FIG. 1). The probe driver 208 is used to rotate ortranslate, e.g., by extending or retracting the probe 206. The probedriver 208, in a particular example, can provide, at a minimum, atranslation of 20-80 mm, 30-70 mm, 40-60 mm or 40 mm, with a maximumtranslation of 60 mm, 80 mm, 100 mm, 120 mm or 60-150 mm. The probedriver 208, further to the example, can also provide, at a minimum, arotation of 300°-340°, with a maximum rotation of 350°, 359°, 360°,540°, 720° or angles therebetween.

Returning to FIG. 1, in certain embodiments, the workstation 106 outputssignals, to the MRI system 110 to initiate certain imaging tasks. Inother implementations, the workstation 106 outputs signals to anintermediary system or device that causes the MRI system 110 to initiatethe imaging tasks. In certain embodiments, the workstation 106additionally outputs signals to the electronics rack 104. Theelectronics rack 104 includes various actuators and controllers thatcontrol the thermal therapy devices, such as, in some examples, acooling fluid pressure and/or a flow rate of the cooling fluid, and apower source that powers a thermal therapy device. In one example of athermal therapy device, the power source is a laser source that outputslaser light via an optical fiber. As illustrated in FIG. 1, theelectronics rack 104 is located in an MRI Equipment Room and includesstorage tanks to hold the cooling fluid, one or more interfaces thatreceive the signals from the control workstation 106 and/or a separateMRI workstation, an energy emission source (e.g. laser), and an outputinterface. One or more of the interfaces are connected with or includephysical wiring or cabling that receives the signals and transmits othersignals, as well as physical wiring or cabling that transmit energy tocorresponding components in the MRI Scan Room through a portal thatroutes the signals and/or energy in a manner that minimizes anyinterface with or by the MRI system 110. The wiring or cabling areconnected at or by the interface platform 102 to correspondingcomponents to effect and actuate control of a thermal therapy deviceand/or an associated thermal therapy session.

In certain embodiments, the system is indicated for use to ablate,necrotize, carbonize, and/or coagulate the targeted tissue area (e.g.,an area of soft tissue) through interstitial irradiation or thermaltherapy, in accordance with neurosurgical principles, with a HIFUthermal therapy device. The HIFU thermal therapy device or probeincludes ultrasonic transducers for directing ultrasonic energy at thetargeted tissue area, causing the tissue to heat. The ultrasonic beam ofthe HIFU probe can be geometrically focused (e.g., using a curvedultrasonic transducer or lens) or electronically focused (e.g., throughadjustment of relative phases of the individual elements within an arrayof ultrasonic transducers). In an ultrasonic transducer array, thefocused beam can be directed at particular locations, allowing treatmentof multiple locations of an ROI without mechanical manipulation of theprobe. The depth of treatment can be controlled by adjusting the powerand/or frequency of the one or more transducers of the HIFU probe.

In certain embodiments, either additionally or alternatively to HIFUthermal therapy, a laser-based thermal therapy is utilized in the MRIsystem. Laser probes of a variety of outputs can be utilized, including,in some examples, laser probes emitting laser light having wavelengthsof 0.1 nm to 1 mm, and laser probes emitting laser light in one or moreof the ultraviolet, visible, near-infrared, mid-infrared, andfar-infrared spectrums. Types of lasers used with respect the laserprobe include, for example, gas lasers, chemical lasers, dye lasers,metal-vapor lasers, solid-state lasers, semiconductor lasers, and freeelectron lasers. In a particular example, one or more wavelengths of thelaser light emitted by the laser probe are within the visible spectrum,and one or more wavelengths of the laser probe are within thenear-infrared spectrum.

In certain embodiments, the environment 100 can be utilized for planningand monitoring thermal therapies effected via MRI-imaging, and canprovide MRI-based trajectory planning for the stereotactic placement ofan MRI compatible (conditional) probe. The environment 100, in certainembodiments provides real-time thermographic analysis of selected MRIimages and thus, temperature feedback information and/or thermal doseprofiles for the targeted tissue area. For example, thermographicanalysis of the MRI images can provide real-time verification ofcellular damage in a targeted tissue area that corresponds to necrosis,carbonization, ablation, and/or coagulation. In another example,thermographic analysis can be used to monitor tissue surrounding aperiphery of an ROI to ensure minimal if any damage to healthy tissues.Components of the environment 100 may assist in guiding, planning,adjusting, performing and confirming a thermal therapy session andtrajectories associated therewith.

A procedure includes, generally, identifying an ROI and/or associatedtargeted tissue areas in a patient that should be treated, planning oneor more trajectories for treating the tissue, preparing the patient andcomponents for the treatment, and performing the treatment. Aspects ofthe various parts of the treatment are described throughout thisdisclosure, and an exemplary sequence of treatment steps is illustratedin FIGS. 4A and 4B.

Turning to FIG. 4A, a process flow diagram illustrates an exemplarymethod 400 for pre-planning a treatment of a patient. In pre-planningthe thermal therapy session, in certain embodiments, pre-treatmentDigital Imaging and Communications in Medicine (DICOM) image data isloaded and co-registered, for example, via the workstation 106(illustrated in FIG. 1). Using the DICOM image data, one or more ROIsand/or targeted tissue areas and one or more initial trajectories can bedetermined and set (402).

In preparation for treatment, in certain embodiments, a head coil andfixation system is attached to the patient (404), for example bypositioning the head coil and stabilization system on the surgicaltable. The patient can be immobilized using a head fixation ring. Toensure stable imaging, for example, the patient's head can be securedwith the head fixation ring and remain fixed for the entire imagingportion of the flow chart in FIG. 4A. An example head fixation system isdescribed in U.S. Provisional Application Ser. No. 61/955,124 entitled“Image-Guided Therapy of a Tissue” and filed Mar. 18, 2014.

Prior to applying thermal energy to an ROI, a probe entry location intothe skull is identified. In certain embodiments, a burr hole is drilledin the skull (406). The burr hole may be drilled prior to attachment ofprobe introduction equipment (e.g., a miniframe, anchoring device, guidestem, instrument sheath, etc.). A twist-drill hole, in certainembodiments, can be created following a trajectory alignment of theprobe introduction equipment. The twist-drill hole can have a size of1-5 mm, 2 mm, 3 mm, 4 mm or 4.5 mm.

The probe introduction equipment, such as a stereotactic miniframe orlow profile anchoring device, in certain embodiments, is attached to thepatient's head (408). Probe aligning equipment, such as the miniframe orguide stem, can then be aligned along the intended trajectory, forexample using image-guided navigation. After attaching the probeintroduction equipment, the head coil can be attached. An exemplary headcoil system is described in U.S. Provisional Application Ser. No.61/955,124 entitled “Image-Guided Therapy of a Tissue” and filed Mar.18, 2014. Depending on a process flow that is specific to a surgicalcenter, the interface platform may be attached prior to or after MRItrajectory confirmation. The order of steps in a site-specific processmay be determined based on members of MRI or surgical support team andmay be determined during on-site training with respect to the MRIsystem. The interface platform (IP) is attached to the head end of thehead coil and stabilization system. Then, the IP power and motor plugsare connected.

In certain embodiments, the patient is positioned in a MRI cabin, andMRI imaging is performed to confirm a trajectory (410) associated with athermal therapy device and/or probe introduction equipment. For example,an MRI trajectory wand may be inserted into the probe introductionequipment for use in confirming its trajectory. The trajectory of theprobe introduction equipment, for example, can be evaluated using MRIimaging prior to inserting a probe into the brain. Volumetric imaging orvolumetric visualization may be captured to include the entire head andfull extent of the probe introduction equipment, independently ofablation. Along with trajectory confirmation, in some examples, beamfiducial marker detection may also be performed. For example, thecaptured images may also display a position of a beam fiducial markerlocated in a portion of the probe introduction equipment. This markercan be detected and identified by the MRI imaging system and method tostore an orientation of the physical direction of the probe. Thecaptured images, in implementations where pre-treatment image data isnot available, can be used for planning a thermal therapy session.

In certain embodiments, a probe actuation and guidance device (e.g., afollower) and a test tool are attached to the probe introductionequipment, to provide positional feedback for a self-test function(412). The self-test function, for example, may be used to confirm thatinputs to the probe actuation and guidance device, (e.g., from theworkstation), accurately and/or precisely drive the probe. Uponcompleting the self-test function, the rotary test tool may be removed.Upon completing the procedure described in relation to FIG. 4A, theprocedure equipment may be introduced and the procedure initiated.

Turning to FIG. 4B, a process flow diagram illustrates an exemplarymethod 420 for a treatment procedure. In certain embodiments, a probe isattached and inserted into the probe introduction equipment and/or thepatient's skull (e.g., secured for manipulation via the probe actuationand guidance device) (422). Exemplary implementations of neurosurgicalprobes are discussed in below under the section entitled “Probes.” It isnoted that different types of probes can be used in conjunctiondifferent types of thermal therapy, for example, when an ROI is not inthe brain. An MRI scan can then be conducted to ensure probe alignmentis correct and confirm movement and delivery of the probe along theintended trajectory. In one example, the acquired image data can bedisplayed, along with pre-planning image data by the workstation 106.Using a graphical user interface (GUI), a user can adjust the probedisplayed by the GUI by interacting with, for example, the GUI to matchthe probe artifact on the acquired image to ensure that the alignmentand arrangement of the probe as physically placed in the probeintroduction equipment and inserted into the patient coincides with therendered probe at the workstation. The probe's trajectory, for example,can be adjusted to a desired position for delivering thermal energy, viainteraction with the GUI. Further, the probe's rotational position canalso be adjusted to a desired direction or angle for thermal delivery,via interaction with the GUI. Once the probe rendering presented by theGUI matches the probe artifact on the display, the user may confirm thetrajectory via the GUI.

In certain embodiments, one or more scan planes are selected for curinga thermal monitoring sequence via the MRI system's sequence protocollist (424). In another embodiment, a 3D volume is selected and in yetanother embodiment, a linear contour is selected. Parameters associatedwith scan plane, in some examples, can be entered by a user via aworkstation connected with the MRI system or directly into the thermalmonitoring sequences protocol's geometry parameters of the MRI.

In certain embodiments, temperature feedback information and/or thermaldose profiles are initialized and monitored (426). For example, under anoise masking heading of the workstation interface, at least threereference points (e.g., six, twelve, twenty, etc.) can be selected bythe user at the periphery of the ROI. The ROI, for example, may includean overlaid, orange noise mask in one or more image monitoring viewpanes to illustrate the intended thermal delivery area. The noisemasking may be used to improve accuracy of temperature monitoring duringtissue treatment.

In certain embodiments, energy delivery via the probe is actuated tobegin the thermal therapy session (428). For example, once “Ready”indicator or the like is displayed under a laser status heading of theGUI at the workstation, the user may depress a foot pedal operativelyconnected to the workstation to deliver thermal energy to the ROI or atargeted tissue area within the ROI. Thermal energy can then be eithercontinuously or intermittently delivered while monitoring thermal doseprofiles, which can be presented as contours that are overlaid onto oneor more (e.g., three) thermal monitoring view panes rendered by the GUIof the work station. Thermal delivery may be halted as desired or asnecessary by releasing the foot pedal. The view panes, for example, maydisplay an energy dose profile or thermal dose profile supplied by theprobe, with respect to a specified time period and/or a specifiedtargeted tissue area or ROI; the thermal dose or energy dose profile canbe displayed as a succession of temperature gradients. The thermal doseprofiles and/or the temperature gradients permit the determination of anextent of cellular damage in the targeted tissue area and/or othereffects upon the targeted tissue area occurring as a result of thethermal therapy.

Once a thermal dose for a particular alignment and positioning of theprobe is completed, if further probe alignments are desired within thetreatment plan (430), a rotational and/or linear alignment of the probemay be adjusted (432) by translating or rotating the probe. For example,an energy output of the probe may be terminated and then the probe maybe subjected to linear translation and/or rotational movement, which canbe controlled, for example, by a probe driver (a particularimplementation of which is illustrated in FIG. 3). After adjusting theprobe alignment, in certain embodiments, the process returns to step 422to verify a current placement of the probe. In certain embodiments, asecond thermal treatment procedure is not initiated (e.g., whenrepeating step 428) until one or more targeted tissue areas within theROI returns to a baseline body temperature. The thermal dose associatedwith the one or more targeted tissue areas in the ROI, as described inrelation to steps 422 through 432, may continue at various proberotational and/or linear alignments until the entire ROI has beentreated.

Upon determining that the thermal therapy is complete (430), shouldtreatment with an additional probe be needed or desired (434), theprocedure can be repeated by attaching the new probe to the probeintroduction equipment and verifying probe placement (422). If, instead,the second probe was initially included within the probe introductionequipment (e.g., via a separate lumen in a guide sheath in relation tothe first probe), the user may initiate positioning of the second probe,for example, via the GUI, and verify placement of the second probe(422). A multi-probe configuration is described in greater detail inrelation to FIG. 5I.

If the second probe is being deployed to treat the same ROI or the sametargeted tissue area at the same linear and rotational alignment(s)associated with the first probe, in certain embodiments, step 424involving selection of scan planes for the curing the thermal monitoringsequence may be skipped. If, instead, a second probe is deployed at adifferent linear position or a different trajectory, step 422 may beperformed to confirm the trajectory and alignment of the second probe.

When the thermal therapy is complete (434), in certain embodiments, thepatient is removed from the MRI bore and the probe, probe actuation andguidance device, and probe introduction equipment are detached from thepatient. The bore hole may be closed, for example, at this time.

II. Low Profile Probe Introduction Equipment

A. Low Profile Skull Anchoring Device

In certain embodiments, when preparing for an intracranial neurosurgicalprocedure, a patient 502 is fitted with a low profile skull anchoringdevice 504, as illustrated in an exemplary mounting illustration 500 ofFIG. 5A. The low profile skull anchoring device 504 may be releasablyattached to the head of the patient 502, for example, using three ormore bone anchors mounted to the skull of the patient 502. Turning toFIG. 5B, the low profile skull anchoring device 504 includes three bonescrews 508 for connecting to bone anchors within the skull of thepatient 502, as well as pins 510 for further securing the low profileskull anchoring device 504 to the head of the patient 502 and forensuring that the low profile skull anchoring device 504 mounts abovethe surface of the head of the patient 502. In this way, there will beminimal or no compression of the patient's scalp. In one embodiment, thelow profile skull anchoring device 504 has an oval or an oblong shape.

In one embodiment, the screws 508 and pins 510 are composed of, forexample, titanium. It should be noted that the screws 508 and the pins510 are not necessarily limited to three pins; the number of screws 508and pins 510 used is the number which is necessary to provide sufficientrigidity. The screws 508 and pins 510 may be evenly spaced around thecircumference of the low profile skull anchoring device 504 (e.g.,positioned approximately every 120 degrees). In another embodiment, thescrews 508 and pins 510 are positioned at unequal distances apart, forexample, based on an irregular skull curvature. In yet anotherembodiment, the screws 508 and the pins 510 are movable with respect tothe low profile skull anchoring device 504. In still another embodiment,the screws 508 are replaced with a sufficiently rigid adhesive or astaple, each of which provide sufficient rigidity to allow for thedrilling of a burr hole in the skull.

Due to the low height of the low profile skull anchoring device 504, themedical team is provided with greater access for lateral trajectories ofbiopsy, probes, and other apparatus to be inserted intracranially intothe patient 502 via the low profile skull anchoring device 504. This maybe especially useful when working within the confines of an MRI bore,for example during MRI-guided thermal therapy treatments. As such, thelow profile skull anchoring device 504 may be composed of MRI compatiblematerials and, optionally, include MRI visible markers for aligning adesired trajectory or defining a particular direction relative to thelow profile skull anchoring device 504. In another example, the lowprofile skull anchoring device 504 may allow easier access toback-of-the-head entry trajectories, such as trajectories used inperforming epilepsy treatments. A mounting height of the low profileskull anchoring device 504, for example, may be thirty millimeters orless from the surface of the skull of the patient 502.

B. Removable Guide Stem

Turning to FIG. 5A, the low profile skull anchoring device 504 includesa removable guide stem 506. The removable guide stem 506, in someexamples, may lock to the low profile skull anchoring device 504 using ascrew mechanism, keyed locking mechanism, or other connector configuredto firmly connect the removable guide stem 502 to the low profile skullanchoring device 504 with relative ease of removal.

Turning to FIG. 5B, the exemplary the low profile skull anchoring device504 includes three connection points 512 for securing the removableguide stem 506 to the low profile skull anchoring device 504. Theremovable guide stem 506, for example, may include a series of guidestem connectors 514 (e.g., screws or locking pins) which mate with theconnection points 512 of the low profile skull anchoring device 504, asshown in FIGS. 5A and 5C. In one embodiment, the alignment of the guidestem connectors 514 and the connection points 512 differs based on askull curvature of the patient.

In another example, the removable guide stem 506 may lock to the lowprofile skull anchoring device 504 using a keyed mechanism, such as aninsert-and-twist slot and tab configuration (not illustrated). In stillfurther examples, the removable guide stem 506 may releasably connect tothe low profile skull anchoring device 504 using retractable lockingpins which mate to corresponding depressions. For example, retractablepins built into the low profile skull anchoring device 504 may beextended to mate with corresponding depressions within the removableguide stem 506. In another example, spring-loaded retractable lockingpins may be pressure-inserted into mating depressions within theremovable guide stem 506, for example by pushing the removable guidestem 506 into the interior diameter of the low profile skull anchoringdevice 502. Further to this example, a latch or button mechanism may beused to retract the locking pins and release the removable guide stem506 from the low profile skull anchoring device 502. Other lockingmechanisms are possible.

A central cylindrical portion of the removable guide stem 506 isconfigured to receive various adapters and/or instruments such as, insome examples, drill bits, biopsy needles, and treatment probes. Thecentral cylindrical portion of the removable guide stem 506, in certainembodiments, is rotatably adjustable, allowing an orientation of centralcylindrical portion of the removable guide stem 506 to be manipulated toalign the probe in accordance with a desired trajectory. Upon alignment,in certain embodiments, a locking mechanism 516 may be actuated to lockthe central cylindrical portion of removable guide stem 506 into placeat the set alignment.

Turning to FIG. 5C, the removable guide stem 506 may include, forexample, a ball joint 518 for establishing an adjustable trajectory forpassing instruments to the skull of the patient 502 via the centralcylindrical portion of removable guide stem 506. In certain embodiments,the central portion has another geometric or polygonal shape thatcorresponds to a cross-section of the probe. In certain embodiments,interior portions of the central cylindrical portion of the removableguide stem 506 are deformable so as to cover an outer surface of theprobe. In still other embodiments, the interior portions of the centralcylindrical guide stem are comprised of shape memory alloys that have atransition temperature that exceeds a maximum temperature associatedwith a specified thermal therapy.

The ball joint 518 can achieve a number of trajectories that is based onthe granularity with which the ball joint 518 is manipulated. Uponsetting the trajectory of the central cylindrical portion of removableguide stem 506, for example, the ball joint 518 may be clamped intoposition using the locking mechanism 516. In one embodiment, the lockingmechanism 516 is a cam lock. In another embodiment, the lockingmechanism 516 is a ring clamp. In still another embodiment, the lockingmechanism 516 has a screw engagement. In another example, the ball joint518, upon positioning of the trajectory, may be clamped into positionusing a ring clamp (not illustrated).

In some implementations, the ball joint may be perforated and/orindented at set increments such that, rather than an infinitelyadjustable trajectory, the removable guide stem 506 has a multipleselection trajectory allowing for precise adjustment. Upon positioning,for example, a screw engagement or locking pin may lock the ball joint518 at the selected position. Further to the example, to aid inprecision adjustment, guide lines or trajectory markers may indicate aselected trajectory (e.g., in relation to a plane of the low profileskull anchoring device 504).

Turning to FIGS. 5D and 5E, illustrative examples of a removable guidestem 520 including both a tilt adjustment 522 and a rotation adjustment524 are shown. The separate tilt adjustment 522 and rotation adjustment524, for example, may be used to more precisely adjust a trajectory ofthe central cylindrical portion of removable guide stem 520. Uponadjusting the tilt adjustment 522, for example, a tilt lock mechanism526, such as a screw and hole or locking pin and pin slot, may beactivated to hold the central cylindrical portion of removable guidestem 520 at the selected tilt position. In another example, uponadjusting the rotation of the central cylindrical portion of removableguide stem 520, for example by turning the rotation adjustment 524, arotation lock mechanism 528, such as a screw and hole or locking pin andpin slot, may be activated to hold the removable guide stem 520 at theselected rotation.

In other implementations, the tilt adjustment 522 and/or rotationadjustment 524 includes a graduated friction lock, such that assertingpressure along the line of adjustment causes the trajectory to “click”to a next incremental setting (e.g., one, two, or five degrees). In thiscircumstance, a user can count a number of clicks to determine a presentrelative trajectory selected. In one embodiment, the graduated frictionlock includes a rack and pinion mechanism. In another embodiment, thegraduated friction lock includes detents and a spring-loaded plunger.

In certain embodiments, guide lines such as a set of guide lines 530 aremarked on the removable guide stem 520 (or the removable guide stem 506illustrated in FIG. 5A) to provide a user with an indication of theselected trajectory. For example, an angle of tilt in relation to thelow profile skull anchor 504 may be selected via the guide lines 530(e.g., within a one, two, or five degree angle of adjustment). The guidelines 530, in certain embodiments, are MR indicators, such that an MRimage captured of the removable guide stem 520 will allow a softwarepackage to register an initial trajectory in relation to the head of thepatient (e.g., patient 502 of FIG. 5A).

In certain embodiments, in addition to a tilt and rotation adjustment,either the first removable guide stem 506 or the second removable guidestem 520 may be modified to include an x,y degree of freedom adjustmentmechanism (not illustrated). In this manner, a position of the centralcylindrical portion of guide stem 506 in relation to a burr hole openingbeneath the low profile skull anchor 504 may be adjusted by the user.Rather than the central cylindrical portion of guide stem 506 or 520being centered within the low profile skull anchor 504, for example, anx,y adjustment mechanism may allow an offset of the central cylindricalportion of removable guide stem 506 or 520. In a particular example,should the burr hole fail to be centered between bone anchors plantedwithin the skull of the patient 502, the central cylindrical portion ofguide stem 506 or 520 may be adjusted by up to at least ten to twentymillimeters to be centered above the burr hole using an x,y adjustmentmechanism.

For example, the x,y adjustment mechanism may be configured using anadjustable spring loaded cam and locking mechanism (e.g., set pin orscrew). In another example, the x,y adjustment mechanism may beconfigured using an adjustable hinge configuration, such that the legsof the “Y” shape of the guide stem 506 are capable of swinging along anadjustment travel of the hinge configuration.

In some implementations, the guide stem 506, rather than being fixedlyconnected to the low profile skull anchor 504, may be adjustablyconnected to the low profile skull anchor 504. For example, the guidestem 506 may connect to an adjustable gantry system, such that the x,ydisplacement of the guide stem 506 can be set through an adjustablegantry. In a further example, the x, y adjustment mechanism can beconfigured using a rotatable ring configured between the low profileskull anchor 504 and the guide stem 506, such that the Y shape of theguide stem 506 may be twisted to a desired trajectory and then the guidestem 506 may be adjusted closer to the low profile skull anchor 504along an adjustment leg of the Y shape. For example, an adjustmentmechanism may be provided along a particular leg of the Y shape suchthat, to implement x,y adjustment, the Y is first rotated into a desiredposition, and then linear travel effected along the adjustment branch ofthe Y.

In some implementations, rather than a Y-shaped removable guide stemmechanism such as guide stem mechanism 506, the removable guide stemmechanism includes an X-shaped connection to aid in x,y adjustment. Inthis configuration, the x,y adjustment mechanism can include a slideablegantry with locking mechanisms such as a clamp or set screw. In anotherexample, the x,y adjustment may include a screw drive, allowing a userto twist and adjust the displacement of the central position of theguide stem 506 in either or both the x direction and the y direction.Further, the spring-loaded cam and/or hinge system adjustment mechanismsdescribed above in relation to the Y-shaped configuration are equallyapplicable to an X-shaped configuration.

Turning to FIG. 5B, upon removal of the removable guide stem 506 or 520,the skull entry location becomes accessible, for example to allow forformation of a burr hole or to otherwise prepare the skull entrylocation. After preparation of the entrance, the removable guide stem506 or 520 may be locked to the low profile skull anchor 504. Forexample, as illustrated in FIG. 5D, the removable guide stem 520 may belocked to the low profile skull anchor device 504 by attaching screws atthree connection locations 532. In another example, the removable guidestem 520 may be clamped to the low profile skull anchor device 504. Atany point in a procedure, should access to the entrance be desired, theguide stem 520 may be removed. Removal of the guide stem 520, forexample, allows a medical professional quick access to react to bleedingor to adjust the burr hole opening for trajectory correction.

When performing a medical procedure via the low profile skull anchoringdevice 504, in certain embodiments, the low profile skull anchoringdevice 504 may first be aligned with screw anchors mounted upon thepatient's skull and then screwed to the head of the patient 502, asillustrated in FIG. 5A. The skull entry location may be prepared fortreatment during the thermal therapy while the removable guide stem 506or 520 has been separated from the low profile skull anchoring device504. Following preparation of the skull entry location, the removableguide stem 506 or 520 may be replaced and its trajectory aligned.

To align the removable guide stem 506, 520 with a desired treatmenttrajectory, in certain embodiments, the removable guide stem 506, 520 isautomatically manipulated. For example, the removable guide stemmanipulation may be performed by software executing upon the commander302 of the probe driver 208 as described in relation to FIG. 3. Inanother example, the removable guide stem 506 may be manipulated via atrajectory planning module of a software system, such as softwareexecuting upon the workstation 106 of FIG. 1. The manipulations of theremovable guide stem 506, 520, for example, may be performed by a probeactuation and guidance device. In a particular example, as described inrelation to the method 400 of FIG. 4A, a test tool may be inserted intothe removable guide stem 506, 520, and the test tool may be aligned withpre-treatment image data to determine an initial trajectory. In anotherexample, automatic manipulation may be supplemented with real timeimages supplied by an image guided system (e.g., MRI-imaging system).For example, the test tool alignment may be monitored and verified by asoftware algorithm through capture of MRI images during manipulation. Inother implementations, an operator manually adjusts the trajectory ofthe removable guide stem 506, 520. Alignment of the trajectory of theremovable guide stem 506, 520, in some implementations, is aided by oneor more guide lines or fiducial markers upon the surface of the lowprofile skull anchoring device 504 and/or upon the surface of theremovable guide stem 506, 520, such as the guide lines 530 illustratedin FIG. 5D.

Upon positioning the trajectory of the removable guide stem 506, 520, incertain embodiments, the trajectory is locked via a locking mechanism,such as the locking mechanism 516 of FIG. 5C or the locking mechanisms526 and 528 of FIG. 5D.

After the removable guide stem 502 has been locked into its initialtrajectory, in certain embodiments, instruments may be guided into theskull via the removable guide stem 506 or 520. For example, biopsytools, a thermal treatment probe, medicament delivery probe, or otherneurosurgical device may be delivered to a ROI of the brain of thepatient via the removable guide stem 506 or 520.

C. Trajectory Positioning

FIG. 6 is a flow chart illustrating an example method 600 fordetermining trajectory adjustments based upon initial position andorientation of probe introduction equipment upon the skull of a patient.The method 600, for example, may be used in determining a trajectoryprior to conducting a neurosurgical procedure. In some implementations,the method 600 is performed by software executing upon the workstation106, as described in relation to FIG. 1. In another example, the method600 is performed by software executing upon the commander 302 of theprobe driver 208 as described in relation to FIG. 3.

In some implementations, the method 600 begins with obtaining an MRIimage of a skull of a patient fitted with probe introduction equipment(602). The MRI image, for example, may be obtained by the MRI system110, as described in relation to FIG. 1. MRI image data including two ormore images, in other examples, may be obtained from a remote medicalsystem, for example through a hospital file transfer system. Further,MRI image data, in some implementations, may be scanned into the systemand loaded into the software.

In some implementations, one or more fiducial markers identifying probeintroduction equipment are determined from the MRI image (604). Forexample, a software system installed upon the workstation 106 can reviewthe MRI image data for graphical data matching a known fiducial markerrelated to probe introduction equipment. For example, a particular shapeor series of shapes may be indicative of the location of probeintroduction equipment, such as the low profile skull anchoring device504 described in relation to FIGS. 5A through 5E or the stereotacticminiframe described in U.S. patent application Ser. No. 13/838,310 toTyc, entitled Image-Guided Therapy of a Tissue and filed Mar. 15, 2013,which is hereby incorporated by reference in its entirety.

In some implementations, if a type of the probe introduction equipmentis unknown (606), a type of the probe introduction equipment may bedetermined based upon one or more of the shapes, sizes, lengths, and/orpositions of the identified fiducial marker(s) (608). For example, basedupon a particular arrangement or shape of fiducial marker, the softwarealgorithm may differentiate the low profile skull anchoring device fromthe stereotactic miniframe. In another example, a particular arrangementof fiducial markers may be used to differentiate a low profile skullanchoring device with an x,y adjustment guide stem from a low profileskull anchoring device with an immobile guide stem.

In other implementations, the type of probe introduction equipment maybe known (606). For example, the software may be bundled with particularprobe introduction equipment such that the fiducial markers are onlyused to identify positioning of the known probe introduction equipment.In another example, a user may manually enter the type of probeintroduction equipment into the software (e.g., through a drop-downselection menu or other selection mechanism). In a further example, acommunication may be received from the probe introduction equipment bythe software, identifying the type or model of probe introductionequipment. In a particular illustration of this example, an algorithmexecuting upon the commander 302 of the probe driver 208 (illustrated inFIG. 3) communicates information regarding the type of probeintroduction equipment to the software.

Once the type of probe introduction equipment has been identified, insome implementations, a position and orientation of the probeintroduction equipment is determined using the identified fiducialmarkers (610). For example, based upon a particular distribution offiducial markers, the software may identify the mounting location of theprobe introduction equipment in relation to the skull of the patient.Fiducial markers, as a particular illustration, may identify therelative locations of the bone screws 508 of the low profile skullanchoring device 504, as illustrated in FIG. 5B. In another example, thetrajectory of the guide stem 506, as illustrated in 5C, may bedetermined based upon an angle of a fiducial marker line or shape uponthe guide stem 506.

The position and orientation of the probe introduction equipment, insome implementations, is determined with reference to the skull of thepatient. For example, identifying relative locations of the bone screws508 based upon fiducial markers upon the low profile skull anchor 504may identify position of the head of the patient. In another example,fiducial marker stickers may be applied to the head of the patient toidentify the head relative to the probe introduction equipment. Featuresof the head of the patient, such as brow, ears, nose, or cheek bones,for example, may be highlighted to orient the position of the lowprofile introduction equipment in relation to the face of the patient.

In other implementations, position and orientation of the probeintroduction equipment is determined relative to imaging or headstabilization equipment. In a first example, the position andorientation of the probe introduction equipment may be determined basedupon one or more fiducial marker reference points on the head coil 202or the head fixation ring 204, as illustrated in FIG. 2.

In some implementations, a position of a portion of the probeintroduction equipment may be identified in relation to other probeintroduction equipment. For example, as described in relation to theguide stems 506 and 520 of FIGS. 5A through 5E, an x,y degree of freedomadjustment mechanism may have been used to modify the position of thecentral cylindrical portion of guide stem in relation to a burr holeopening beneath the probe introduction equipment. If the centralcylindrical portion of the guide stem is offset in relation to the lowprofile skull anchoring device 504, for example, the software maycalculate the position of the offset.

In some implementations, a representation of the probe introductionequipment is overlaid on the displayed MRI image (612). For example,based upon the type, position, and orientation determined above, thesoftware may overlay a reference image (e.g., semi-transparent image,dotted outline, etc.) representing the location of at least a portion ofthe probe introduction equipment. For example, a position andorientation of the guide stem 506 attached to the low profile anchoringdevice 504 (e.g., as illustrated in FIGS. 5A and 5C) may be presented tothe user. The overlaid image, in some embodiments, mimics the look anddesign of the actual probe introduction equipment. In other embodiments,the overlaid image is a simple dotted line orientation image that maybear little similarity to the look of the actual equipment.

In some implementations, a target region of interest in the skull of thepatient is determined (614). For example, as described in step 402 ofthe method 400, discussed with reference to FIG. 4A, pre-treatment imagedata may be used to identify one or more treatment regions of interest.In one example, a user may manually identify a region of interest, forexample by highlighting or circling the region of interest within theMRI image. The region of interest, for example, may include a tumor orportion of a tumor. In some implementations, the region of interest isidentified as a three-dimensional location within the skull of thepatient. For example, the region of interest may identify a target pointfor a tip of a probe to reach. In other implementations, the region ofinterest may identify a three-dimensional volume. For example, theregion of interest may describe a tumor or a portion of a tumor to betreated.

In some implementations, a trajectory is determined for reaching thetarget region of interest (616). For example, the software may identifyan access path leading from the probe introduction equipment (asidentified by via the fiducial markers) to the region of interest. Theaccess path, in some implementations, depends upon features of the braindiscerned to be within a general path leading from the probeintroduction equipment to the target region of interest. The featuresavoided by the software, for example, may include the brain stem,particularly fibrous tissues or major arteries. To identify the featuresof the brain to avoid, in some implementations, the software analyzesMRI images of the patient to identify known delicate and/or difficult totraverse features. In other implementations, a user may highlight withinscanned images of the patient's brain one or more features to avoid whenselecting a trajectory.

In some implementations, the software identifies two or more potentialaccess paths and selects between the access paths. For example,depending upon particularly delicate or difficult to maneuver featuresof the brain between the region of interest and the position of theprobe introduction equipment, the software may select between two ormore possible access paths to identify the path least likely to causedifficulties during the procedure. The two or more possible accesspaths, in one example, include a path to one end of a target volumeversus a path to another end of a target volume. In another example, thetwo or more possible access paths include two or more curved accesspaths to a single target point. The curved access path, for example, maybe determined based upon identification of therapeutic instruments thatwill be used during the procedure. For example, a user may identify aparticular probe or other equipment capable of curved trajectory towardsa region of interest. A pre-shaped probe, for example, may be designedto deploy from the probe introduction equipment 210 (e.g., a guidesheath or guide stem) at a particular angle of curvature. The software,for example, upon receiving identification of the probe being used, mayaccess data regarding the angle of curvature of the selected probe. Inanother example, the software algorithm may recommend a deploymentdevice (e.g., guide sheath, guide sleeve, etc.) including an offsetdistal opening at a particular angle to effect the desired curvedtrajectory of a flexible cannula or laser fiber. For example, asillustrated in FIG. 5I, the off-axis delivery hole 558 may be used todeploy the flexible cannula or laser fiber at a particular angle.

In some implementations, a flexible cannula or laser fiber can beautomatically directed along a trajectory. For example, a flexiblecannula or laser fiber may be capable of curved guidance using magneticsteering. In this example, one or more gradient coils may be used toguide the flexible cannula or laser fiber along a curved path to accessa region of interest. In this example, the software may accesscapabilities of the magnetic steering system and flexible cannula orfiber to determine potential trajectory paths. Determining thetrajectory, further to this example, may include determining commands toprovide to a magnetic steering system to guide the flexible cannula orlaser fiber to the region of interest.

In a further example, a robotic steering device such as a robotic wormmay be used to pull a flexible neurosurgical instrument towards theregion of interest along the curved access path. For example, therobotic worm may be remotely controlled to navigate a path towards adifficult to access region of interest while pulling or otherwisefeeding the flexible neurosurgical device into position. In anotherexample, the robotic worm may be programmed to follow a predeterminedpath to the region of interest such that, upon deployment (e.g., via aguide sheath or rigid cannula), the robotic worm steers the flexibleneurosurgical instrument into position at the region of interest. Therobotic worm, in some implementations, is further designed to create apath, for example through fibrous tissue, by cutting or bluntly pushingaside tissue to provide access for the flexible neurosurgicalinstrument. In some implementations, determining the trajectory includesdetermining commands to provide to the robotic worm to guide theflexible neurosurgical instrument to the region of interest.

In some implementations, one or more recommended adjustments for settinga trajectory of the probe introduction equipment are determined basedupon the location of the region of interest and the initial position andorientation of the probe introduction equipment (618). In someimplementations, the software identifies one or more adjustment featuresand/or ranges of motion of the particular type of probe introductionequipment. For example, using the guide stem 506 described in relationto FIG. 5C, the software may identify that the guide stem 506 has aninfinitely adjustable trajectory via the ball joint, and based uponpresent orientation, to achieve the desired trajectory, a user may wishto align the guide stem 506 with particular guide lines. Similarly,based upon identification of the removable guide stem 520 having boththe tilt adjustment 522 and the rotation adjustment 524, the softwarealgorithm may identify two separate adjustments for setting the desiredtrajectory, both the tilt adjustment and the rotation adjustment (e.g.,as identified by guide lines or other adjustment markers (or “clicks”)of the tilt adjustment 522 and/or the rotation adjustment 524).

If the probe introduction equipment includes an x,y degree of freedomadjustment mechanism for adjusting the position of the centralcylindrical portion of guide stem in relation to the low profile skullanchoring device, the software may identify adjustment ranges of the x-ydegree of freedom adjustment mechanism and recommend a modified offsetof the guide stem to align with an optimal trajectory for reaching theregion of interest.

In some implementations, the one or more recommended adjustments areprovided for review by a medical professional (620). For example, theadjustments may be presented upon a display in communication with theworkstation 106. In another example, the adjustments may be presentedupon the display region of the interface platform 102 (as illustrated inFIG. 2) such that a user may review the instructions while setting thetrajectory of the probe introduction equipment. In some implementations,in addition to the recommended adjustments, a displaced positioning ofthe representation of the probe introduction equipment may be overlaidon the displayed MRI image (e.g., illustrating the recommended alignmentof the adjusted probe introduction equipment with the region ofinterest).

Using the recommended adjustments, for example, the medical professionalmay manually adjust the probe introduction equipment to the newtrajectory. In other implementations, the probe driver 208 (illustratedin FIG. 3) and/or other automated equipment may be used instead or incoordination with manual adjustments to align the trajectory of theprobe adjustment equipment. For example, the software may issue commandsto the probe driver 208 to adjust a trajectory of the guide stem afterreceiving confirmation from a user that the guide stem locking mechanismis in an unlocked position. Upon positioning, the software may promptthe user to engage the locking mechanism, locking the guide stem intoposition.

After adjusting the trajectory, in some implementations, the user mayrequest confirmation of desired trajectory via the software. To confirmthe trajectory setting, for example, the software may compare presentfiducial marker alignment with anticipated fiducial marker alignment(e.g., based upon change in position of the fiducial markers). Inanother example, the software may re-calculate a trajectory using thepresent fiducial markers and verify that the new trajectory aligns withthe region of interest. The software, in a third example, may calculatean anticipated trajectory based upon the identified alignment (e.g.,based upon a present position of the fiducial markers) and compare theanticipated trajectory to the trajectory calculated in step 616. Shouldthe adjustment be misaligned for some reason, at least steps 616 and 618of the method 600 may repeated as necessary.

D. Guide Sheath

Turning to FIGS. 5F and 5G, in certain embodiments, rather thaninserting instruments directly into the removable guide stem 506 or 520,a guide sheath 540 is inserted into the removable guide stem (e.g.,removable guide stem 506). The guide sheath 540 may include, forexample, one or more distal openings and one or more proximal openingsto introduce at least one neurosurgical instrument to the ROI in thepatient's brain.

In certain embodiments, instead of using the guide sheath 540 configuredfor receipt of neurosurgical devices, a hollow trocar may be introducedvia the removable guide stem 506 or 520 to prepare an initial entry intoa region of the brain. For example, when entering a particularly fibrousarea, rather than pushing in directly with a neurosurgical instrumentand risking damage to the neurosurgical instrument, a trocar orstylette, may be used to cut a path for the neurosurgical instrument.The stylette or trocar, for example, may have a sharp distal opening tocut a path through the fibrous area. In another example, the trocar orstylette may have a bullet shaped nose to bluntly push tissue out of thetrajectory path. In other implementations, a stylette or trocar may beintroduced to the region of interest via the guide sheath 540.

In certain embodiments, the guide sheath 540 locks to the removableguide stem 506. The guide sheath 540, for example, may be configured tolock to the removable guide stem 506 at a variable linear heightdepending upon a distance between the skull opening and a ROI. In thismanner, the guide sheath 540 may be deployed in proximity to, in thevicinity of, or adjacent to an ROI without abutting or entering the ROI.As such, upon removal of one or more neurosurgical instruments via theguide sheath 540, cells from the ROI will not be able to contaminateother regions of the patient's brain. In some implementations, a “wiper”mechanism designed into the distal end of the guide sheath 540 may aidin avoiding contaminants within the guide sheath 540.

Turning back to FIG. 5C, in certain embodiments, a guide stem lockingmechanism 519 may be used to clamp the guide sheath 540 at a particularlinear depth. The guide sheath 540, in a particular example, may havespaced indentations or other connection points for interfacing with theguide stem locking mechanism 519 (e.g., set screw or spring-loadedplunger). In other embodiment, the guide sheath may have spacedratcheting teeth for interfacing with a ball plunger or toggle release.The indentations (or, alternatively, ratcheting teeth) may be positionedat precise measurements (e.g., 1 mm apart) to aid in linear positionadjustment. In other examples, the guide sheath 540 and guide stemlocking mechanism 519 may be configured to provide positive feedback toa medical professional during adjustment. For example, a linear actuatorsystem such as a rack and pinion may be used to provide precise linearposition adjustment (e.g., one “click” per millimeter). Upon adjustment,to lock the guide sheath 540 at the selected linear position, in certainembodiments a cam lock mechanism may be used to engage teeth ordepressions within the guide sheath 540. For example, a cam lockmechanism such as the locking mechanism 516 illustrated in FIG. 5C maybe used to lock the guide sheath 540 at a selected linear depth.

Turning back to FIG. 5D, the removable guide stem 520 similarly includesa guide stem locking mechanism 534. In other implementations, the guidesheath 540 may directly connect to the low profile skull anchoringdevice 504 or to another receiving port connected to the low profileskull anchoring device 504 (not illustrated).

The guide sheath 540, upon interlocking with the guide stem 506, 520and/or the low profile skull anchoring device 504 and receiving one ormore neurosurgical tools, may create an air-tight seal during aneurosurgical operation. For example, the proximal and/or distal end ofthe guide sheath 540 may include a receiving port adaptable to thesurgical instrument being introduced. For example, the proximal and/ordistal end of the guide sheath 540 may include an adjustable aperturethat may be dialed or electronically set to a particular diametermatching a present neurosurgical instrument. In certain embodiments,various guide sheaths can be used interchangeably with the guide stem506, 520, such that a guide sheath corresponding to the surgicalinstrument diameter may be selected. In other implementations, one ormore guide sleeves (not illustrated) may be secured inside the guidesheath 540, each of the one or more guide sleeves having a differentdistal end diameter. A divided (e.g., bifurcated) guide sleeve, incertain embodiments, may be used to introduce two or more instrumentssimultaneously or concurrently, each with a particular instrumentdiameter.

In certain embodiments, the guide sheath 540 is intracranially deliveredusing an introducer and guide wire. An image guidance system, such asthe MRI imaging system, may be used instead of or in addition to theintroducer and guide wire during placement of the guide sheath 540. Theguide sheath 540 may be composed of MRI compatible materials.

The materials of the guide sheath 540, in certain embodiments, areselected to provide rigid or inflexible support during introduction ofone or more neurosurgical tools within the guide sheath 540. Forexample, the guide sheath 540 may be composed of one or more of Kevlar,carbon fiber, ceramic, polymer-based materials, or other MRI-compatiblematerials. The geometry of the guide sheath 540, in certain embodiments,further enhances the strength and rigidity of the guide sheath 540.

In certain embodiments, the guide sheath 540 (or guide sleeve, asdescribed above) includes two or more lumens for introduction of variousneurosurgical instruments. By introducing two or more neurosurgicalinstruments via the guide sheath 540, a series of treatments may beperformed without interruption of the meninges layer between treatments.For example, FIG. 5I illustrates two neurosurgical instruments 552 and554 that are simultaneously inserted into a guide sheath 550 and can beused to carry out treatment of a tissue consecutively, concurrently, orsimultaneously.

Neurosurgical instruments deployed via the guide sheath 540 may exit asame distal opening or different distal openings. In certainembodiments, the guide sheath 540 may include at least one off-axisdistal opening. For example, as illustrated in FIG. 5H, exemplary guidesheath 550 includes a contact surface 556 having a predefined angle.Upon encountering the contact surface 556, the trajectory of a surgicalinstrument 552 presented through the guide sheath 550 may be deflectedto exit the proximal end via an off-axis delivery hole 558, asillustrated in FIG. 5I. The angles shown in FIGS. 5H and 5I can beconsidered as drawn to scale in one implementation. However, thealignment of the contact surface 556 and the delivery hole 558 can bevaried by adjusting their respective axial angles. By adjusting theseangles, a number of possible positions of the surgical instrument 554are provided. Further, multiple off-axis delivery holes and multiplecontact surfaces can be provided, which are displaced from each other ina direction of the longitudinal axis of the guide sheath.

Upon introducing a neurosurgical instrument such as a probe, in certainembodiments, the guide sheath 540 enables coupling between the probe anda probe actuation and guidance device. For example, commands for linearand/or rotational control of the probe may be issued to the probe via aninterface within the guide sheath 540.

III. Probe

A number of different probes can be utilized in accordance with thevarious aspects presented in this disclosure. Example probes aredescribed in: U.S. Pat. No. 8,256,430 to Torchia, entitled “HyperthermiaTreatment and Probe Therefor” and filed Dec. 17, 2007; U.S. Pat. No.7,691,100 to Torchia, entitled “Hyperthermia Treatment and ProbeTherefor” and filed Aug. 25, 2006; U.S. Pat. No. 7,344,529 to Torchia,entitled “Hyperthermia Treatment and Probe Therefor” and filed Nov. 5,2003; U.S. Pat. No. 7,167,741 to Torchia, entitled “HyperthermiaTreatment and Probe Therefor” and filed Dec. 14, 2001; PCT/CA01/00905,entitled “MRI Guided Hyperthermia Surgery” and filed Jun. 15, 2001,published as WO 2001/095821; and U.S. patent application Ser. No.13/838,310, entitled “Image-Guided Therapy of a Tissue” and filed Mar.15, 2013. These documents are incorporated herein by reference in theirentireties.

A number of probe lengths are provided in any of the probe examplesdescribed herein based on a degree of longitudinal travel allowed by afollower and a depth of the tissue to be treated. An appropriate probelength can be determined by the interface platform and/or theworkstation during a planning stage, or determined during a trajectoryplanning stage.

Exemplary probe lengths can be indicated on the probes with reference toa probe shaft color, in which white can indicate “extra short” having aruler reading of 113 mm, yellow can indicate “short” having a rulerreading of 134 mm, green can indicate “medium” having a ruler reading of155 mm, blue can indicate “long” having a ruler reading of 176 mm, anddark gray can indicate “extra long” having a ruler reading of 197 mm.Different model numberings can also be utilized on the probes toindicate different lengths.

In general, a therapeutic window of wavelengths for thermal therapyusing a laser probe ranges from 800 to 1100 nm. Wavelengths lower than800 (e.g., within the visible spectrum) lack the energy to effectivelyheat tissue, while wavelengths above 1100 nm rapidly heat an immediateregion, thereby being useful in applications such as tattoo removalwhere a thin region is burned. In some implementations, a laser probehas a 1064 nm wavelength for coagulation of tissue. The 1064 nmwavelength, for example, is selected based upon water absorptionproperties of laser wavelengths. By minimizing water absorption, forexample, depth of penetration can be maximized. The 1064 nm laser probe,for example, may be used to apply thermal therapy to a three-dimensionalzone approximately two to four centimeters in diameter. Thus, the 1064nm wavelength allows deeper penetration and provides a higher powerdensity associated with energy application so as to more efficientlyeffect thermal therapy. In certain embodiments, the laser probe iscooled via Joule-Thompson cooling, which eliminates and/or minimizesenergy absorption and scatter, as discussed in further detail below.

In some implementations, the laser probe is a side-firing laser probe tofocus the energy of the 1064 nm wavelength laser. For example, beyondthe penetration zone of the laser probe (e.g., about two to fourcentimeters), the photon scattering can cause difficulties in focusingthe therapy. Depth of penetration may be improved through focusing alaser beam using a side-firing design. Similar benefits may be achievedin designing a side-firing HIFU probe, as described below.

An energy output pattern of a probe, such as a laser probe or HIFUprobe, in certain embodiments, includes a pulsed output pattern. Forexample, a higher power density may be achieved without causing tissuescorching by pulsing a high power laser treatment for x seconds with yseconds break between (e.g., allowing for tissue in the immediatevicinity to cool down). Furthermore, pulsing allows the system to varyenergy delivered to a region of interest without affecting the powerdensity applied to the region of interest. In this manner, higher energycan be applied to a region of interest without causing damage (e.g.,scorching) to immediate tissue. In a particular example, the energyoutput pattern of a probe may include a ten Watt output for 2 to 2.5seconds followed by a one to 1.5 second period of inactivity (e.g.,delivering approximately 398 Joules per minute). In certain embodiments,a particular energy output pattern may be developed based upon the typeof probe (e.g., laser, HIFU, etc.), an emission style of the probe tip(e.g., side-firing, diffuse tip, etc.), and/or the depth of the ROIand/or the targeted tissue area (e.g., based in part on the shape of atumor region, etc.). For example, in a diffuse tip design, the energyoutput pattern for the diffuse tip probe may include a ten Watt outputfor 2 seconds, followed by a 0.3 second period of inactivity (e.g.,delivering approximately 500 Joules per minute).

In some implementations, based upon feedback received through thermalimaging, the energy output pattern may be adjusted. For example, theperiod of inactivity may be lengthened or shortened depending upon atemperature gradient between the tissue closest to the probe and thedepth of treatment (e.g., the furthest tissue being thermally ablated).In another example, the power output of the probe may be adjustedinstead of or in addition to the period of inactivity, based uponthermal imaging feedback. For example, to increase a treatment radius,the power density supplied by the probe may be increased.

In some implementations, to further guard against tissue scorching, thelaser probe may include a cooling tip to cool tissue within theimmediate vicinity. During the period of inactivity between pulses, forexample, the tip of the laser probe may cool to approximately 0 to 5degrees Celsius. A cryogenic cooling device (e.g., cooling tube) may bedesigned into a 1064 nm wavelength side-firing laser probe, in aparticular example, to affect cooling to surrounding tissue duringinactive periods between energy pulses. A thermocouple within thecooling device, further to the example, can be read during inactiveperiods to avoid interference caused by energy emission. The 1064 nmwavelength allows deeper penetration and higher power density; that is,thermal therapy can cause cellular damage to a targeted tissue region ina shorter period of time.

In certain embodiments, a treatment pattern includes effecting treatmentwhile concurrently or simultaneously moving the probe (e.g., linearlyand/or rotationally). For example, a HIFU probe may be automaticallyrotated (e.g., using a commander and follower as described in FIG. 3,etc.) while an emission pattern is simultaneously or concurrentlyadjusted to effect treatment to a desired depth based upon a particulargeometry of the ROI. In this manner, for example, while the ultrasonicprobe's beam is focused on a radial portion of the tumor having a depthof 1.5 centimeters, the power density of the HIFU probe may be tuned forthe first treatment depth. Upon rotation, a second radial portion of thetumor may have a depth of 2 centimeters, and the power density of theHIFU probe may be increased accordingly to tune for the treatment depthof 2 centimeters. If two or more ultrasonic transducers are included inthe HIFU probe, the power may be varied on a per-transducer basis or tothe entire transducer array.

A. Side-Fire HIFU Probe

Turning to FIG. 7A, a view 700 of an exemplary treatment scenarioinvolving a HIFU probe 702 deployed to treat an ROI 706 is illustrated.HIFU technology advantageously provides directional control and greaterdepth penetration as compared with laser-based thermal therapy. Forexample, in comparison to laser therapy, ultrasonic therapy may achieveat least three to four times greater depth penetration. For example,estimated depths of thermal treatment using HIFU technology includethree to five centimeters or greater than six centimeters. By completingtreatment via an initial trajectory, the treatment may be performedfaster and less invasively than it may have been performed using a laserprobe. As such, a HIFU probe may be used to treat a larger ROI withoutthe need to adjust a probe trajectory or introduce the probe intomultiple locations within the brain. Although treatment may be providedat a greater depth, it also may be provided using a narrow focal beam,containing a width of the treated tissue. Furthermore, althoughHIFU-based thermal therapy can advantageously achieve a greaterpenetration depth than laser-based thermal therapy, the ultrasonictreatment has greater uniformity over temperature gradients thanlaser-based thermal therapy, which heats a portion of the targetedtissue area close to the probe much more rapidly than portions of thetargeted tissue area further away from the probe. In selecting thermaltherapy via a HIFU probe, scorching or carbonization of the targetedtissue area close to the probe may be avoided and/or the HIFU probe maybe operated independently of external cooling to protect immediatelysurrounding tissue.

In performing thermal therapy using a HIFU probe, constructive anddestructive interference can be utilized by selecting a number ofdifferent longitudinal spaced emission points to fine tune a positionand depth of energy applied to a targeted tissue area and/or an ROI. Assuch, the depth of energy, as such, may be tuned to conform with anon-uniform, irregular, and/or non-polygonal shape of the ROI which, forexample, corresponds to a tumor. For example, power supplied to thetransducers of a side firing HIFU probe may be varied as the HIFU probeis rotated to a new position, thereby adjusting penetration of theultrasonic energy to a depth of the a region of interest (e.g., tumor)at the present angle of rotation. In this manner, HIFU treatment may beused to “sculpt” an irregularly shaped three-dimensional lesionconforming to a region of interest through power variance duringrotation of the probe. As noted above, because HIFU treatment may reacha penetration depth of three to five centimeters or even greater thansix centimeters, it is imaginable that an irregularly-shaped tumor of atleast 5 centimeters in diameter may be treated without the need toadjust an initial trajectory of the HIFU probe. In certain embodiments,the side-fire HIFU probe may treat an ROI having a tumor volume of up to110 cubic centimeters. In other embodiments, the side-fire HIFU probemay treat an ROI having a tumor volume with a range of approximately 0.1cubic centimeters and 110 cubic centimeters. Preparing trajectories,determining linear translational adjustments and/or rotationalmovements, and/or energy output patterns may be selected and/oroptimized to prevent heating of the skull and/or bouncing energy off ofthe surfaces of the skull. HIFU treatment, in some examples, can be usedfor opening a blood-brain barrier, coagulation of tissue, or cavitationof tissue.

The HIFU probe 702 includes one or more side-firing transducers 704 foreffecting treatment to the ROI 706. The ultrasonic transducer(s) 704 maybe flat or rounded. The HIFU probe, in some examples, can include ashaft composed of plastic, brass, titanium, ceramic, polymer-basedmaterials, or other MRI-compatible materials in which one or moreultrasonic transducer(s) 704 have been mounted. The ultrasonictransducer(s) 704 may be mounted upon an interior surface of the shaftof the HIFU probe 702. The ultrasonic transducer(s) 704 may include alinear array of individually controllable transducers, such that afrequency or power output of each transducer 704 may be individuallytuned to control a treatment beam of the HIFU probe 702. For example, asillustrated in FIG. 7C, the tip of the probe 702 can include a lineararray of three transducers 704. The longitudinally spaced aparttransducers 704 can be spaced equally apart. However, in otherimplementations, the spacing between the transducers 704 can be unequal.

In certain embodiments, the HIFU probe 702 includes a cooling mechanismfor cooling the ultrasonic transducers 704. For example, a cooling fluidor gas may be delivered to the tip of the HIFU probe 702 to control atemperature of the ultrasonic transducer(s) 704. Additionally, theultrasonic transducer(s) 704 may be surrounded by an acoustic medium,such as an acoustic coupling fluid (e.g., water) to enable ultrasonicfrequency tuning of the ultrasonic transducer(s) 704.

As illustrated in FIG. 7A, the HIFU probe 702 is embedded within an ROI706 spanning multiple MR thermal monitoring planes 708. Duringtreatment, thermal effects within each MR thermal monitoring plane 708may be monitored in order to monitor thermal coagulation of the ROI 706.Information derived from the thermal monitoring, for example, may be fedback into control algorithms of the HIFU probe 702, for example, toadjust a power intensity and/or frequency of the HIFU probe to tune adepth of treatment of the ultrasonic beam or to adjust a rotationaland/or linear positioning of the HIFU probe 702 upon determining thatablation is achieved at a current rotational and linear position.

To increase the monitoring region, additional MR thermal monitoringplanes 708 may be monitored (e.g., between four and eight planes, up totwelve planes, etc.). Alternatively, in certain embodiments, the threethermal monitoring planes 708 may be spread out over the y-axis suchthat a first gap exists between plane 708 a and plane 708 b and a secondgap exists between plane 708 b and plane 708 c. The thermal monitoringalgorithm, in this circumstance, can interpolate data between the MRthermal monitoring planes 708.

In other implementations, rather than obtaining parallel images of MRthermal monitoring planes, at least three thermal monitoring planes,each at a distinct imaging angle bisecting an axis defined by aneurosurgical instrument such as a thermal ablation probe, may beinterpolated to obtain thermal data regarding a three-dimensionalregion.

Turning to FIG. 8A, an aspect illustration 800 demonstrates three MRthermal monitoring planes 802 for monitoring ablation of an ROI 804 by aprobe 806. The angles between the thermal monitoring planes, in someexamples, may be based upon an anatomy of the region of the skull of thepatient or a shape of the ROI. The angles, in some examples, may differby at least ten degrees.

Turning to FIG. 8B, an end view 810 of the probe 806 provides anillustrative example of MR thermal monitoring planes 802 that are eachoffset by sixty degrees. In comparison to using parallel MR thermalmonitoring planes, the thermal monitoring planes 802 provide a morerealistic three-dimensional space. Temperature gradients and/or thermaldose profiles between the thermal monitoring planes 802 can beinterpolated. Similar to increasing a number of parallel MR thermalmonitoring planes, in other implementations, four or more thermalmonitoring planes may be captured and combined, for example, to increasethermal monitoring accuracy.

As a result of the side-firing capability of the HIFU probe 702, anumber of rotationally different portions of the ROI can be treated withthe ultrasonic energy by rotating the HIFU probe 702. For example, asillustrated in an x-axis sectional view 710, the HIFU probe 702 may berotated is illustrated in an arrow 712 to effect treatment throughoutthe ROI 706. Additionally, the HIFU probe 702 can be longitudinallytranslated, for example automatically by a follower of a probe driver,to change a longitudinal position at which ultrasonic energy is appliedwithin the ROI 706.

Rotation, power intensity, duty cycle, longitudinal positioning, andcooling, in certain embodiments, are controlled by the electronics rack104 and the workstation 106, such as the electronics rack 104 andworkstation 106 described in relation to FIG. 1. A sequence, such as analgorithm or software encoding, can be executed to cause a probe tip ora number of probe tips to execute a particular energy output patterneffect a predefined thermal therapy to a targeted tissue area. Theenergy output pattern can be based on rotational and/or longitudinalmovements of the probe.

The procedures and routines described herein can be embodied as asystem, method or computer program product, and can be executed via oneor more dedicated circuits or programmed processors. Accordingly, thedescriptions provided herein may take the form of exclusively hardware,exclusively software executed on hardware (including firmware, residentsoftware, micro-code, etc.), or through a combination of dedicatedhardware components and general processors that are configured byspecific algorithms and process codes. Hardware components are referredto as a “circuit,” “module,” “unit,” “device,” or “system.” Executablecode that is executed by hardware is embodied on a tangible memorydevice, such as a computer program product. Examples include CDs, DVDs,flash drives, hard disk units, ROMs, RAMs and other memory devices.

FIG. 9 illustrates an example processing system 900, and illustratesexample hardware found in a controller or computing system (such as apersonal computer, i.e., a laptop or desktop computer, which can embodya workstation according to this disclosure) for implementing and/orexecuting the processes, algorithms and/or methods described in thisdisclosure. The processing system 900 in accordance with this disclosurecan be implemented in one or more the components shown in FIG. 1. One ormore processing systems can be provided to collectively and/orcooperatively implement the processes and algorithms discussed herein.

As shown in FIG. 9, the processing system 900 in accordance with thisdisclosure can be implemented using a microprocessor 902 or itsequivalent, such as a central processing unit (CPU) and/or at least oneapplication specific processor ASP (not shown). The microprocessor 902is a circuit that utilizes a computer readable storage medium 904, suchas a memory circuit (e.g., ROM, EPROM, EEPROM, flash memory, staticmemory, DRAM, SDRAM, and their equivalents), configured to control themicroprocessor 902 to perform and/or control the processes and systemsof this disclosure. Other storage mediums can be controlled via acontroller, such as a disk controller 906, which can controls a harddisk drive or optical disk drive.

The microprocessor 902 or aspects thereof, in alternate implementations,can include or exclusively include a logic device for augmenting orfully implementing this disclosure. Such a logic device includes, but isnot limited to, an application-specific integrated circuit (ASIC), afield programmable gate array (FPGA), a generic-array of logic (GAL),and their equivalents. The microprocessor 902 can be a separate deviceor a single processing mechanism. Further, this disclosure can benefitfrom parallel processing capabilities of a multi-cored CPU.

In another aspect, results of processing in accordance with thisdisclosure can be displayed via a display controller 908 to a displaydevice (e.g., monitor) 910. The display controller 908 preferablyincludes at least one graphic processing unit, which can be provided bya number of graphics processing cores, for improved computationalefficiency. Additionally, an I/O (input/output) interface 912 isprovided for inputting signals and/or data from microphones, speakers,cameras, a mouse, a keyboard, a touch-based display or pad interface,etc., which can be connected to the I/O interface as a peripheral 914.For example, a keyboard or a pointing device for controlling parametersof the various processes and algorithms of this disclosure can beconnected to the I/O interface 912 to provide additional functionalityand configuration options, or control display characteristics. An audioprocessor 922 may be used to process signals obtained from I/O devicessuch as a microphone, or to generate signals to I/O devices such as aspeaker. Moreover, the display device 910 can be provided with atouch-sensitive interface for providing a command/instruction interface.

The above-noted components can be coupled to a network 916, such as theInternet or a local intranet, via a network interface 918 for thetransmission or reception of data, including controllable parameters. Acentral BUS 920 is provided to connect the above hardware componentstogether and provides at least one path for digital communication therebetween.

The workstation shown in FIG. 1 can be implemented using one or moreprocessing systems in accordance with that shown in FIG. 9. For example,the workstation can provide control signals to peripheral devicesattached to the I/O interface 912, such as actuators 924 to drive probepositioning and actuation equipment. The workstation, in someimplementations, can communicate with additional computing systems, suchas an imaging unit 926 and/or an MRI unit 928, via the I/O interface912.

One or more processors can be utilized to implement any functions and/oralgorithms described herein, unless explicitly stated otherwise. Also,the equipment rack and the interface platform each include hardwaresimilar to that shown in FIG. 9, with appropriate changes to controlspecific hardware thereof.

Reference has been made to flowchart illustrations and block diagrams ofmethods, systems and computer program products according toimplementations of this disclosure. Aspects thereof are implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in acomputer-readable medium that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablemedium produce an article of manufacture including instruction meanswhich implement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer orother programmable data processing apparatus to cause a series ofoperational steps to be performed on the computer or other programmableapparatus to produce a computer implemented process such that theinstructions which execute on the computer or other programmableapparatus provide processes for implementing the functions/actsspecified in the flowchart and/or block diagram block or blocks.

A number of implementations have been described. Nevertheless, it willbe understood that various modifications may be made without departingfrom the spirit and scope of this disclosure. For example, preferableresults may be achieved if the steps of the disclosed techniques wereperformed in a different sequence, if components in the disclosedsystems were combined in a different manner, or if the components werereplaced or supplemented by other components. The functions, processesand algorithms described herein may be performed in hardware or softwareexecuted by hardware, including computer processors and/or programmablecircuits configured to execute program code and/or computer instructionsto execute the functions, processes and algorithms described herein.Additionally, some implementations may be performed on modules orhardware not identical to those described. Accordingly, otherimplementations are within the scope that may be claimed.

The invention claimed is:
 1. A method for effecting thermal therapyusing an in vivo side fire laser probe, comprising: positioning the sidefire laser probe in a volume in a patient at a target position;identifying a three-dimensional region of interest at which to applythermal therapy; and delivering, by processing circuitry, thermaltherapy to the three-dimensional region of interest, wherein deliveringthermal therapy comprises applying a pulsed energy output pattern by a)activating emissions exiting the side fire probe at a power output for afirst period of time, b) deactivating emissions exiting the side fireprobe for a second period of time, wherein the second period of time isselected to avoid tissue scorching, and c) repeating steps a) and b),while directing the pulsed energy output pattern in an initialtrajectory until determining completion of thermal therapy at theinitial trajectory, wherein the pulsed energy output pattern isdelivered at a higher power density than achievable without causingtissue scorching using a constantly active energy output; whereindetermining completion of thermal therapy at the initial trajectorycomprises at least one of i) identifying the three-dimensional region ofinterest has reached a target temperature, and ii) identifying a thermaldose that is based on a temperature history of the three-dimensionalregion of interest over a specified time period.
 2. The method of claim1, further comprising, after determining completion of thermal therapyat the initial trajectory: positioning the side fire probe in thepatient at a second target position by causing actuation of the sidefire probe, by the processing circuitry, in at least one of a rotationaldirection and a linear direction; and delivering, by the processingcircuitry, thermal therapy to the three-dimensional region of interestby applying a second pulsed energy output pattern to thethree-dimensional region of interest at a second trajectorycorresponding to the second target position.
 3. The method of claim 1,wherein the second period of time is at least 0.3 second.
 4. The methodof claim 1 wherein a wavelength of energy delivered by the side fireprobe is 1064 nanometers.
 5. The method of claim 1, wherein deliveringthermal therapy to the three-dimensional region of interest furthercomprises activating, by the processing circuitry, cooling of anemission region of the side fire probe while the emissions aredeactivated from exiting the side fire probe.
 6. The method of claim 5,further comprising: controlling the cooling of the emission region ofthe side fire probe to hold the side fire probe at a temperature that iswithin a specified temperature range.
 7. The method of claim 5, whereindelivering thermal therapy to the three-dimensional region of interestfurther comprises reading, by the processing circuitry, a thermocoupleof the side fire probe while the emissions are deactivated from exitingthe side fire probe.
 8. A system for effecting thermal therapy using anin vivo side fire laser probe, comprising: a processor; and a memoryhaving instructions stored thereon, wherein the instructions, whenexecuted by the processor, cause the processor to: identify athree-dimensional region of interest at which to apply thermal therapywithin a volume of a patient, wherein the side fire laser probe ispositioned in the volume; identify, based upon one or more of a) a probetype, b) a probe emission style, and c) a depth of the three-dimensionalregion of interest, a pulsed energy output pattern, wherein the pulsedenergy output pattern comprises an active duration and an inactiveduration, wherein the inactive duration is selected to avoid tissuescorching, and the pulsed energy output pattern is delivered at a higherpower density than achievable without causing tissue scorching using aconstantly active energy output; and cause application of the pulsedenergy output pattern to the three-dimensional region of interest alonga first trajectory, wherein causing application of the pulsed energyoutput pattern comprises a) activating probe emission for the activeduration at a power output, b) deactivating probe emission for theinactive duration, c) repeating steps a) and b) while monitoringfeedback data until identifying, based upon the feedback data, evidenceof potential damage to tissue proximate an emission region of the probe;d) responsive to identifying the evidence of potential damage, adjustingat least one of a) a period of the inactive duration and b) a period ofthe active duration to avoid overheating the tissue closest to theemission region, and e) continuing to repeat steps a) and b) whilemonitoring further feedback data until identifying, based upon thefurther feedback data, conclusion of the thermal therapy; wherein thefeedback data and further feedback data comprise at least one oftemperature-sensitive data and imaging data, and the feedback data andfurther feedback data are provided by at least one of a magneticresonance (MR) imaging system and a thermometry imaging system.
 9. Thesystem of claim 8, wherein the active duration is at least 1 second. 10.The system of claim 8, wherein identifying the three-dimensional regionof interest comprises identifying the three-dimensional region ofinterest within Digital Imaging in Communications and Medicine (DICOM)format data.
 11. The system of claim 8, wherein the instructions, whenexecuted, further cause the processor to capture, via magnetic resonance(MR) imaging equipment, magnetic resonance (MR) image data of thepatient, wherein identifying the three-dimensional region of interestcomprises identifying the three-dimensional region of interest withinthe MR image data.
 12. The system of claim 8, wherein causingapplication of the pulsed energy output pattern further comprises,responsive to identifying the evidence of potential damage, adjustingthe power output.
 13. The system of claim 8, wherein: monitoringfeedback data comprises determining a temperature at tissue closest tothe emission region of the side fire probe; and adjusting the period ofthe inactive duration comprises lengthening the period of the inactiveduration responsive to the temperature at the tissue to avoidoverheating the tissue closest to the emission region of the side fireprobe.
 14. A non-transitory computer readable medium having instructionsstored thereon, wherein the instructions, when executed by a processor,cause the processor to: identify a three-dimensional region of interestat which to apply thermal therapy within a volume of a patient using alaser probe, wherein the laser probe is positioned in the volume;identify a pulsed energy output pattern, wherein the pulsed energyoutput pattern comprises an active duration, a target energy level, andan inactive duration, wherein the inactive duration is selected to avoidtissue scorching, and the pulsed energy output pattern is delivered at ahigher power density than achievable without causing tissue scorchingusing a constantly active energy output; and cause application of thepulsed energy output pattern to the three-dimensional region of interestby the probe in an initial trajectory, wherein causing application ofthe pulsed energy output pattern comprises a) activating probe emissionfor the active duration at the target energy level, b) deactivatingprobe emission for the inactive duration, and c) repeating steps a) andb) while monitoring feedback data, until identifying, within thefeedback data, evidence comprising at least one of i) evidence ofpotential damage to tissue proximate to an emission region of the probe,and ii) evidence of a mismatch between a target depth of treatment andan actual depth of treatment, and d) responsive to identifying theevidence, adjusting at least one of the inactive duration and the activeduration.
 15. The computer readable medium of claim 14, wherein causingapplication of the pulsed energy output pattern further comprisesrepeating steps a) and b) while monitoring feedback data untildetermining completion of thermal therapy, wherein determiningcompletion comprises at least one of i) identifying thethree-dimensional region of interest has reached a target temperature,and ii) identifying a thermal dose that is based on a temperaturehistory of the three-dimensional region of interest over a specifiedtime period.
 16. The computer readable medium of claim 14, wherein:monitoring the feedback data comprises applying thermographic analysisof MR images; and identifying the three-dimensional region of interesthas reached the target temperature comprises indicating cellular damagewithin the three-dimensional region of interest.
 17. The computerreadable medium of claim 14, wherein causing application of the pulsedenergy output pattern further comprises, during the inactive duration,activating cooling of the emission region of the probe.
 18. The computerreadable medium of claim 17, wherein activating probe emission comprisestransmitting one or more control signals to an energy emission source toactivate energy emission of a side fire probe that directs energy viauncoated fiber tip; and activating cooling of the emission region of theprobe comprises transmitting one or more control signals to a coolingfluid source to select one of a cooling fluid pressure and a coolingfluid flow rate to circulate gas around the emission region of theprobe.
 19. The computer readable medium of claim 16, wherein identifyingthe three-dimensional region of interest has reached the targettemperature comprises identifying indication of cell death.
 20. Thecomputer readable medium of claim 16, wherein identifying thethree-dimensional region of interest has reached the target temperaturecomprises identifying indication of reversible cell damage.